- Cat. 3 Iridium lens: These iridium lenses in unbreakable polycarbonate like all iridium-treated lenses, irrespective if clear or dark. provide the wearer with 100% anti-UV protection. EKOI has specially chosen these lenses for their exceptional quality. Like all sunglasses, they should be handled with care, the iridium treatment is more effective than a standard lens in intense sunlight.